Most compositions and devices currently used for downhole purposes are manufactured to be hydrolytically resistant—withstanding high temperature(s) and extreme pH environments for prolonged periods of time. Although these compositions can withstand extreme environments, these compositions and devices do not readily degrade and often require physical (e.g., milling) and/or chemical (e.g., strong inorganic acids or bases) stimulus to be introduced downhole to degrade and remove these compositions.
Although there are several degradable compositions currently known, these degradable compositions also face the same problems—requiring physical or chemical stimulus such as those discussed above in order to acceptably degrade and remove these compositions downhole post-use. For example, these degradable compositions are comprised of a metal-based alloy matrix and/or polyglycolic acid. For example, U.S. Pat. No. 7,647,964 discloses a polymeric ball sealer that degrades when contacted with, for example, acidified water, ammonium chloride, potassium chloride, etc. As another example, U.S. Pat. No. 9,528,343 discloses ball sealers formed of a dissolvable aluminum-based alloy matrix containing, for example, gallium with graphitic carbon particulate, and salt particulate, which dissolve in water upon mechanical agitation in the presence of gallium in a generally neutral pH. Even though several degradable compositions for downhole use are currently known, none of these compositions readily degrade downhole—with each requiring introduction of some form of physical and/or chemical stimulus to initiate and/or complete degradation of these compositions, which is time consuming, cumbersome, and costly.